Add warning suppression for keystoneauth loggers
Add warning suppression for keystoneauth loggers

In our simple_logging helper function, add a null logger for
keystoneauth base auth plugin to suppress the "no handler found"
warning.

Change-Id: Ie210e76142a6c3dc731e937e82f12572932f07e0

openstack/python-openstacksdk,stackforge/python-openstacksdk,openstack-infra/shade,openstack/python-openstacksdk,dtroyer/python-openstacksdk,openstack-infra/shade,dtroyer/python-openstacksdk,stackforge/python-openstacksdk